The present invention relates to wireless point to multipoint systems. Systems are known in which a base station transmits electromagnetic signals to, and receives electromagnetic signals from, subscriber units within a sector allocated to the base station. User devices are attached to each subscriber unit, and the base station forwards data to the user devices through their corresponding subscriber units as the data is received by the base station from an outside source, for example the Internet. In one type of known system, the base station designates certain time periods, called “contention periods,” in which the subscriber units are eligible to transmit back to the base station. If a subscriber unit has data to be forwarded to the base station, the subscriber unit does so during the contention period.
Wireless systems are also known which do not have contentions periods but which divide up the available time into slots during which each subscriber unit is allowed to transmit back to the base station. The number of slots is directly related to the number of subscribers in the sector. These type systems also tend to incorporate base stations which will reserve a portion the available bandwidth for traffic from the subscriber to the base station and a percentage of available bandwidth for traffic from the base station to the subscriber.
Wireless systems are known that include a plurality of user devices connected to a subscriber unit that wirelessly communicates with a base station. When the base station receives an Ethernet packet destined to one of the user devices, the base station refers to a database table that associates each user device with its subscriber unit. The table includes a predetermined limit of user devices, for example eight, that may be associated with a subscriber unit in the table at any time. In searching for a user device address in the table, such systems search sequentially through the table addresses for the desired address. Accordingly, such tables are limited in the number of user devices that can be associated with any given subscriber unit and become inefficient in use of the table as the number of entries increases. To reduce the numbers of entries, multiple subscriber units may be attached to a switch, the address of which is then provided in the table.